Aggregation-driven, re-entrant isotropic phase in a smectic liquid crystal material
Year: 2016
Type: article
Abstract: An azobenzene-core chiral mesogen designed for a photoactive ferroelectric liquid crystal system with switchable polarisation displays a highly unusual phase sequence, with a re-entrant, optically isotropic, fluid phase found below smectic phases in mixtures with high enantiomeric purity. The re-entrant isotropic phase is found on the basis of X-ray scattering and freeze-fracture transmission electron microscopy experiments not to be a cubic or other highly ordered phase but instead a translationally disordered liquid. The material also forms a gel under a wide range of concentrations in 50:50 ethanol/chloroform solutions. Ultraviolet/visible and infrared spectroscopy and quantum chemistry calculations suggest that the primary unit in the re-entrant isotropic and gel phases is a dimer composed of molecules crossed by about 90°, which hinders the formation of crystal phases and forms tubules of helical aggregates in the gel phase.
Source: Liquid Crystals
Authors: Jonathan G. Fernsler, Matthew A. Glaser, Renfan Shao, David A. Coleman, Joseph E. Maclennan, Darren R. Link, Catherine Chang, Kenneth Lanham, David Walba, Cecile Boyer, Joseph A. Zasadzinski, Noel A. Clark
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: Division of Materials Research
Awards: G1821513860, G3078429399
OpenAlex ID: W2561242899